RFR(M) 8201447: C1 does backedge profiling incorrectly

[Igor Veresov]

C1 incorrectly incremented a back branch counter for both arms of a conditional branch if one of the arms were a back branch. This fix makes the increment conditional and applicable only to the appropriate arm.

Webrev: http://cr.openjdk.java.net/~iveresov/8201447/webrev.01/

Internal performance testing showed no adverse effects of the change.

Thanks,
igor